Deidra should get 33 questions correct and 12 questions incorrect if she completes a tests with 45 questions.
If the ratio of incorrect questions to total questions is 8:30, that can be simplified down to 4:15.
There are 3 15's in 45 so you need to multiply 4 by 3 to get 12 incorrect answers.
To work out the amount of correct answers, you need to take the incorrect answers away from the total questions.
